Burglar-alarm.



T. H. NELSON.

BURGLAR ALARM.

APPLICATION FILED FEB.28.1913.

Patented Feb. 9, 1915.

THE NORRIS PETERS CO. PHOTO-LITHQ. WASHINGTON. D. c

T. H. NELSON.

BURGLAR ALARM.

APPLICATION FILED 151113.28, 1913.

1,127,91 6. Patented Feb. 9, 1915.

2 SHEETS-SHEET 2.

'HE NORRIS PETERS CO., PHOTO-LITHO.. WASHINGTON, B4 c,

THEODORE II. NELSON, OF CHICAGO, ILLINOIS.

BURGLAR-ALARM.

Application filed February 28, 1913.

T0 aZZ whom it may concern:

Be it known that T, THEODORE H. NELSON, citizen of the United States, residing at Chicago, in the county of Cook and State of Illinois, have invented a certain new and useful Improvement in Bui'glar-r'ilarms, of which the following is a full, clear, concise, and exact description, reference being had to the accompanying drawings, forming a part of this specification.

My invention relates to burglar alarms and contemplates the provision of a simple and efficient device which may be associated with a door or window, particularly a door, and which is adapted to control the circuit for an electrically operated signaling device, such as a bell or gong when the said door or window is opened or the device tampered with in any way. The various parts constituting the device are so constructed and arran 'ed that the electrical contacts are located within hollow casings where they cannot be reached without affecting the electrical circuit controlling the signaling device.

The present invention is particularly concerned with a device which is applicable to doors. Inasmuch as it is almost invariably desirable to have the manual switch control ling the alarm circuit located within the building equipped with the burglar alarm, some means should be provided to prevent the actuation of the signaling device when the person who has charge of the burglar alarm opens the door to leave the building, but which means does not interfere with the actuation of the signal when the door is surreptitiously opened or the burglar alarm devices tampered with. t is with the provision of a device so equipped that the present invention is concerned.

My invention is set forth in detail in the following description, and is illustrated in the accompanying drawings, in which:

Figure l is a front view of a circuit controlling device embodying my invention. Fig. 2 is a plan View thereof. Fig. 3 is a side elevational view thereof. Fig. 4 is a sectional view thereof, illustrating the same used in connection with a normally open electrical circuit arrangement, the contact operating members of the device being shown in their positions at the time the person in charge of the burglar alarm is leavlu the building. Fig. 5 is a viewsimilar to Fig. 4., showing the contact operating de vices in the positions to which they are Specification of Letters Patent.

' Patented Feb. 9, 1915. Serial No. 751,286.

moved when the door is closed. Fig. 6 shows the positions of the contact operating devices and the condition of the alarm circuit after the door is again opened. Fig. 7 is a front elevational view of the preferred form of circuit controlling device embodying my invention. Fig. 8 is a cross-sectional view thereof taken on the line 8-8 of Fig. 7. Fig. 9 is a cross-sectional view thereof, taken on the line 99 of Fig. 7. Fig. 10 illustrates the device shown in Figs. 7 to 9 inclusive, associated with a door and Fig. 11 shows a normally closed circuit arrangement which is adaptable for use with the circuit controlling devices of my invention.

Similar reference numerals refer to similar parts throughout the several views.

The embodiment of my invention illustrated in Figs. 1 to 6 inclusive comprises a plate 12, adapted to be secured upon a door casing by screws or other suitable means. Cast integral with the plate 12, are substantially parallel tubular members 13 and 14, the portions 13 and 14 of which are adapted to be disposed in suitable holes in the door casing. Supported by suitable insulation 15 and extending into the tubular member 13, is a pair of spring contacts 16, which tend to engage each-other. Supported by suitable insulation 17, and extending into the tubular member 14: is another pair of contacts 18, which do not normally engage each other. Secured upon the movable door element is a plate 19, which is provided with a pair of substantially L-shaped integral arms 20 and 21, the far ends of which are designed to lie directly over the outside ends of tubular members 13 and 1-1, when the movable door element is in closed position. The arm 20 is provided with a pin 22, adapted to project into the tubular member .13, and separate the spring contacts therein.

Associated with the member 141- is a plug 23, provided with a shoulder 23 as shown. The said plug carries a pin 2% of conductive material, which, when the parts are in the positions shown in Figs. 5 and 6, is disposed between springs 18, electrically connecting the same.

In the circuit arrangement shown in Figs. 3'- and 6 inclusive, one of the spring contacts of each pair is electrically connected with one spring of the other pair. The other spring of each pair is included in circuit with the source of current 25, by means of a conductor 26, in which is interposed a manually operated switch 27 and an electromagnet 28, controlling a drop 29.

When the burglar alarm is to be placed in operative condition the procedure is as follows: The door with which the plate carrying arms 20 and 21 is associated is opened far enough to draw pin 22 out of engagement with the longer one of contact springs 16. The plug 23 is then moved to the position shown in Fig. 4. The switch 27 is then closed. The circuit for the electromagnet is not closed however owing to the fact that electrical connection between contact springs 18 has been broken. When the door is closed upon the person in charge leaving the building, the parts are moved to the positions shown in Fig. 5. The pin 22 disengaging the contact springs 16 and the pin 24 electrically connecting springs 18. The parts are so conformed that the pin 22 disengages 16 before electrical connection be- 18 is established. If the door be again opened the pin 22 supported by the movable door element will be withdrawn from engagement with the longer of the springs 16. Owing to the fact that the plug 23 isv not mechanically connected with the movable door element the opening of the door does not affect the same. As the pin 22 is withdrawn from the hollow member 13, the circuit including the electromagnet 28 is closed energizing the electromagnet and releasing the drop controlled thereby. As the drop is released, it closes the circuit for a bell or other alarm device illustrated at 30.

In the preferred form of circuit controlling device illustrated in Figs. 7, 8 and 9, the hollow members 13 and is are carried by a plate 12 adapted to be secured upon a door casing. The hollow members 13 and 1 1 are provided with contact springs and insulation corresponding to the parts shown in Figs. 1 to 6 inclusive. The plug 28 within the member 1 1 is provided with a pin 31 riding in a slot 32, which pin prevents the plug from being entirely withdrawn from the member 14*. The plate 19 takes the form of a stamping provided with an upturned portion 33, to which is adjustably secured by means of screws 34, the flange 35 of the plate 36, carrying a pin 22*, as shown. Carried by the member 19 is a leaf spring 37 which holds the plug 23 rigid in operative position when the parts are disposed as shown in Fig. 9. The spring 37 is preferably secured by means of a nut threaded on the screw 34, as shown. The conformation and relation of the various parts is such that as the door is closed the operation is as follows: The pin 22 engages the longer of contacts 16*, the spring 37 engages plug 23 and moves it to actuated position. The spring is then depressed and the plate 36 moves to the position shown in Fig. 9. It should be noted that when the parts are in the spring tween springs the positions shown in Figs. 8 and 9, the flange 35 of the plate 36, prevents tampering with the plug 23*.

In Fig. 11 T have shown a normally closed circuit arrangement which is a desirable one for use with the device of my invention. In this arrangement when the parts are in set position, the pin 22 electrically connects a pair of contact springs, thus closing the circuit for an electromagnet 20 control ling a drop 41. When the person in charge of the burglar alarm cesires to leave the building, he draws the plug 23 out of engagement with the contacts controlled thereby, thus temporarily closing the circuit including the same and maintaining actuation of the electromagnet. After the door is closed, the pin 22 electrically connects the contacts associated therewith before the pin 23 disengages the contacts controlled thereby. When the door is again opened the pin 22 being withdrawn from engagement with its contacts, breaks the circuit including said contacts, deenergizes the electromagnet and thus releases the drop 41. The drop when released, closes the circuit for a bell or other alarm devices illustrated at 4:2.

While I have illustrated my invention in the particular embodiments herein shown, and described, I do not wish to be limited to these exact constructions, but desire to claim broadly any equivalents thereof which may suggest themselves to those skilled in the art.

Nhat I claim and ters Patent of the United States is:

1. In a circuit controlling device for a burglar alarm system, a member adapted to be carried by one element of a door or window, said member comprising two sets of contacts, a second member adapted to be carried by the other element of the door or window, said member carrying means for operating one set of said contacts, and means separate from said second member but actuated by the second element of the door or window for operating the other set of contacts.

desire to secure by Let- 2. In a circuit controlling device for a I burglar alarm system, a member adapted to be carried by one element of a door or window, said member comprising two sets of contacts, a second member adapted to be carried by the other element of the door or window, said second member carrying means for operating one set of said contacts, and means separate from said second member but actuated by the second element of the door or window when the latter is moved to its closed position for operating the other set of contacts.

3. In a circuit controlling device for a burglar alarm system, two sets of contacts adapted to be carried by one element of a door or window,

means carried by the other element adapted to operate one set of said contacts, and means carried by the first element but moved to operative position by the second element, for operating the other set of contacts.

4:. In a circuit controlling device for a burglar alarm system, two sets of contacts adapted to be carried by the stationary element of a door or window, means carried by the movable element adapted to operate one set of said contacts, and means carried by the stationary element adapted to operate the other set of contacts and actuated by the movable element when the latter is moved to closed position.

5. A circuit controlling device for a burglar alarm system comprising two sets of contacts associated with the stationary element of a door or window, and devices adapted to operate said contacts, the operating device for one set of contacts being carried by the movable element of the door or window, and the operating device for the other set of contacts being carried by the stationary element but being moved to operative position by the movable element of the door or window when the latter is moved to its closed position.

6. A circuit controlling device for a burglar alarm system comprising a plate adapted to be supported by one element of a door or window, said plate carrying a pair of hollow members, contacts within said hollow members, and a second plate adapted to be supported by the other element of the door or window, said second plate carrying a pin adapted to project in one of said hollow members to operate the contacts therein, and a plug actuated by the movable element of the door or window when the latter is moved to closed position disposed in the other hollow member and provided with a pin adapted to operate the contacts therein.

7. A circuit controlling device for a bur glar alarm system, comprising a plate adapted to be supported by one element of a door or window, said plate carrying a pair of hollow members, contacts within said hollow members, and a second plate adapted to be supported by the other element of the door or window, said second plate carrying a pin adapted to project in one of said hollow members to operate the contacts therein, and a plug actuated by the movable element of the door or window when the lat ter is moved to closed position disposed in the other hollow member and provided with a pin adapted to operate the contacts therein, said plug having pin and slot connection with its hollow member.

8. A circuit controlling device for a burglar alarm system comprising two sets of contacts associated with a door or window, operating devices for said contacts, and means adapted to actuate the operating devices for both sets of contacts by the door or window when the latter is closed, and retract the operating devices for one set of contacts only when the door or window is opened.

9. In a circuit controlling device for a burglar alarm system, two contact mechanisms arranged to be carried by one element of a door or window, means carried by the other element arranged to operate one of said contact mechanisms, and means carried by the first element, but actuated by the second element for operating the other contact mechanism.

In witness whereof I hereunto subscribe my name this 20th day of February, A. D., 1913.

THEODORE H. NELSON.

WVi-tnesses:

ALBERT O. BELL, LEONARD W. N OVANDER.

Copies of this patent may be obtained for five cents each, by addressing the Commissioner of Patents, Washington, D. G. 

